1. Field of the Invention
This invention relates to tractor-drawn agricultural implements which cover a wide swath, and more particularly, to a hydraulic folding system for such implements. The folding system is designed to be completely automatic, so that the equipment operator is not required to leave the operator station either for folding or unfolding the implement.
2. Description of the Related Art
The following patents relate to hydraulic folding systems for farm implements:
______________________________________ Patent No. Inventor(s) Date ______________________________________ 3,944,001 Warner et al 1976 4,031,965 Blair 1977 4,043,099 Cheatum 1977 4,047,575 Wagner 1977 4,660,654 Wiebe et al 1987 4,813,489 Just et al 1989 ______________________________________
Warner et al describes a hydraulic folding system for a disc cultivator in which the wing folds 180.degree. on top of the main section for transport. There are no special shoulder fulcrums in Warner et al, and the folding is over the top of the main section from the auxiliary section. There is only one auxiliary section, and it is lifted through a vertical arc, which puts quite a strain on the hydraulic lifting mechanism.
Blair describes a wing folding kit having a centrally mounted, floating cylinder with linkage arms hinged on its ends. These arms are attached by lost motion links to cross members of the wings. When the central cylinder contracts, the wings are folded vertically or horizontally. A hydraulic cylinder on the central drawbar section is connected to move all the sections to a vertical position, and then the wings are folded forward. Blair appears to have all the folding motions of the subject invention, but has no special shoulder fulcrums or a support stand for the wing sections. There is only one hydraulic cylinder for folding both wings of the implement.
Cheatum describes a hydraulic system to swing a baler between a field position and a transport position without the operator leaving the seat on the tractor. Solenoids control the hydraulic valves, and the solenoids are controlled from the tractor to move the baler between field and transport positions.
The Wagner patent is directed to a folding apparatus which has a lost motion connection with the main section of his disc harrow to permit the wing section to float up and down about its longitudinal pivot connection to the main section. Wagner has an abutment member disposed above a part of the slot to insure that the end of the jack will not shift from its position at the laterally outer end of the slot. The wings are first raised to a vertical position, and then folded back instead of forward.
Wiebe et al is primarily concerned with an automatically pivoted biased latch. Each wing is folded upwardly to a vertical position for transport, and there is no forward folding of a wing section. The foldable packer harrow implement of Just et al folds to a vertical position, and then folds back, not forward (See FIG. 4).